79 research outputs found

    Dynamic adaptation of delayed time of diffusion of emergency messages in cognitive vehicular networks

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    [ES] En este artículo se presenta un protocolo de difusión de mensajes de seguridad para emergencia que utiliza una adaptación dinámica del tiempo de retraso en el entorno de una red vehicular cognitiva. El escenario que se estudia considera la compartición del espectro entre la banda para comunicaciones vehiculares y la banda de la televisión digital con el objetivo de mitigar los efectos de la tormenta de difusión en una red vehicular. Dos de las técnicas de mitigación de la tormenta de difusión más utilizadas en la literatura son comparadas contra el protocolo propuesto en términos de las probabilidades de accesibilidad de los mensajes de emergencia y de la ocupación del canal. Los resultados numéricos muestran que el protocolo con la adaptación dinámica del tiempo presenta un mejor desempeño en condiciones de alta densidad de vehículos, lo cual es característico de un escenario de tormenta de difusión.[EN] This article presents a protocol for the dissemination of emergency safety messages that uses a dynamic adaptation of the delay time in the environment of a cognitive vehicular network. The scenario studied considers the spectrum sharing between the band for vehicular communications and the digital television band with the objective of mitigating the effects of the diffusion storm on a vehicular network. Two of the most commonly used diffusion mitigation techniques in the literature are compared against the proposed protocol in terms of the probabilities of reachability of emergency messages and channel occupancy. The numerical results show that the protocol with the dynamic adaptation of the time presents a better performance in conditions of high density of vehicles, which is characteristic of a diffusion storm scenario.El presente trabajo de investigación ha sido parcialmente financiado por el Consejo Nacional de Ciencia y Tecnología ( CONACYT) de México a través de la Beca Nacional para Estudios de Posgrado no. 445821.Avalos Gómez, JU.; Stevens-Navarro, E.; Pineda-Rico, U.; Cárdenas-Juárez, M.; Arce, A.; González, S. (2020). Adaptación dinámica del tiempo de retraso de difusión de mensajes de emergencia en redes vehiculares cognitivas. Revista Iberoamericana de Automática e Informática industrial. 17(3). https://doi.org/10.4995/riai.2019.12067OJS284173Avalos Gómez, J. U., Pineda-Rico, U., Cardenas-Juarez, M., Garcia- Barrientos, A., Arce, A., Stevens-Navarro, E., nov 2018. Broadcast storm mitigation of esms using spectrum sharing in cognitive radio vanets. In: 2018 International Conference on Mechatronics, Electronics and Automotive Engineering (ICMEAE). pp. 102-107. https://doi.org/10.1109/ICMEAE.2018.00026Bechler, M., Horozovic, A., Kastner, R., 2015. Evaluation of car-2-x scenarios for automated driving. In: FAST-zero'15: 3rd International Symposium on Future Active Safety Technology Toward zero traffic accidents. pp. 397-402.Bi, Y., Shan, H., Shen, X. S., Wang, N., Zhao, H., mar 2016. A multi-hop broadcast protocol for emergency message dissemination in urban vehicular ad hoc networks. IEEE Transactions on Intelligent Transportation Systems 17 (3), 736-750. https://doi.org/10.1109/TITS.2015.2481486Feukeu, E. A., Zuva, T., dec 2017. Overcoming broadcast storm problem in a vehicular network. In: 2017 13th International Conference on Signal-Image Technology Internet-Based Systems (SITIS). pp. 402-407. https://doi.org/10.1109/SITIS.2017.72IEEE802.11p, jul 2010. Ieee standard for information technology- local and metropolitan area networks- specific requirements- part 11: Wireless lan medium access control (mac) and physical layer (phy) specifications amendment 6: Wireless access in vehicular environments. IEEE Std 802.11p-2010 (Amendment to IEEE Std 802.11-2007 as amended by IEEE Std 802.11k-2008, IEEE Std 802.11r-2008, IEEE Std 802.11y-2008, IEEE Std 802.11n-2009, and IEEE Std 802.11w-2009), 1-51. https://doi.org/10.1109/IEEESTD.2010.5514475Khattab, A., Bayoumi, M. A., may 2015a. An overview of ieee standardization efforts for cognitive radio networks. In: 2015 IEEE International Symposium on Circuits and Systems (ISCAS). pp.982-985. https://doi.org/10.1109/ISCAS.2015.7168800Khattab, A., Bayoumi, M. A., dec 2015b. Standardization of cognitive radio networking: a comprehensive survey. annals of telecommunications - annales des télécommunications 70 (11), 465-477. https://doi.org/10.1007/s12243-015-0468-5Korkmaz, G., Ekici, E., Özgüner, F., jun 2006. An efficient fully ad-hoc multi-hop broadcast protocol for inter-vehicular communication systems. In: 2006 IEEE International Conference on Communications. Vol. 1. pp. 423-428. https://doi.org/10.1109/ICC.2006.254764Korkmaz, G., Ekici, E., Özgüner, F., Özgüner, U., 2004. Urban Multihop broadcast protocol for inter-vehicle communication systems. In: Proceedings of the 1st ACM International Workshop on Vehicular Ad Hoc Networks. VANET '04. ACM, New York, NY, USA, pp. 76-85. https://doi.org/10.1145/1023875.1023887Lim, J., Kim, W., Naito, K., Yun, J., Cabric, D., Gerla, M., nov 2014. Interplay between tvws and dsrc: Optimal strategy for safety message dissemination in vanet. IEEE Journal on Selected Areas in Communications 32 (11), 2117-2133. https://doi.org/10.1109/JSAC.2014.1411RP02Pagadarai, S., Lessard, B. A., Wyglinski, A. M., Vuyyuru, R., Altintas, O., 2013. Vehicular communications, enhanced networking through dynamic spectrum access. IEEE Vehicular Technology Magazine 8, 93-103. https://doi.org/10.1109/MVT.2013.2268659Sahoo, J., Wu, E. H., Sahu, P. K., Gerla, M., sep 2011. Binarypartition-assisted mac-layer broadcast for emergency message dissemination in vanets. IEEE Transactions on Intelligent Transportation Systems 12 (3), 757-770. https://doi.org/10.1109/TITS.2011.2159003Singh, K. D., Rawat, P., Bonnin, J. M., 2014. Cognitive radio for vehicular ad hoc networks (cr-vanets): Approaches and challenges. EURASIP Journal on Wireless Communications and Networking 2014, 49. https://doi.org/10.1186/1687-1499-2014-49Sum, C., Villardi, G. P., Rahman, M. A., Baykas, T., Tran, H. N., Lan, Z., Sun, C., Alemseged, Y., Wang, J., Song, C., Pyo, C., Filin, S., Harada, H., jul 2013. Cognitive communication in tv white spaces: An overview of regulations, standards, and technology [accepted from open call]. IEEE Communications Magazine 51 (7), 138-145. https://doi.org/10.1109/MCOM.2013.6553690Suthaputchakun, C., Dianati, M., Sun, Z., jul 2014. Trinary partitioned black-burst-based broadcast protocol for time-critical emergency message dissemination in vanets. IEEE Transactions on Vehicular Technology 63 (6), 2926-2940. https://doi.org/10.1109/TVT.2013.2293020Tsukamoto, K., Oie, Y., Kremo, H., Altintas, O., Tanaka, H., Fujii, T., apr 2015. Implementation and performance evaluation of distributed autonomous multi-hop vehicle-to-vehicle communications over tv white space. Mobile Networks and Applications 20 (2), 203-219. DOI: https://doi.org/10.1007/s11036-015-0576-5Wisitpongphan, N., Tonguz, O. K., Parikh, J. S., Mudalige, P., Bai, F., Sadekar, V., dec 2007. Broadcast storm mitigation techniques in vehicular ad hoc networks. IEEE Wireless Communications 14 (6), 84-94. https://doi.org/10.1109/MWC.2007.4407231Wu, L., Nie, L., Fan, J., He, Y., Liu, Q., Wu, D., 2017. An efficient multi-hop broadcast protocol for emergency messages dissemination in vanets. Chinese Journal of Electronics 26 (3), 614-623. https://doi.org/10.1049/cje.2017.03.00

    The DAMIC-M experiment: Status and first results

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    The DAMIC-M (DArk Matter In CCDs at Modane) experiment employs thick, fully depleted silicon charged-coupled devices (CCDs) to search for dark matter particles with a target exposure of 1 kg-year. A novel skipper readout implemented in the CCDs provides single electron resolution through multiple non-destructive measurements of the individual pixel charge, pushing the detection threshold to the eV-scale. DAMIC-M will advance by several orders of magnitude the exploration of the dark matter particle hypothesis, in particular of candidates pertaining to the so-called “hidden sector.” A prototype, the Low Background Chamber (LBC), with 20g of low background Skipper CCDs, has been recently installed at Laboratoire Souterrain de Modane and is currently taking data. We will report the status of the DAMIC-M experiment and first results obtained with LBC commissioning data

    TET proteins regulate the lineage specification and TCR-mediated expansion of iNKT cells

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    TET proteins oxidize 5-methylcytosine in DNA to 5-hydroxymethylcytosine and other oxidation products. We found that simultaneous deletion of Tet2 and Tet3 in mouse CD4+CD8+ double-positive thymocytes resulted in dysregulated development and proliferation of invariant natural killer T cells (iNKT cells). Tet2-Tet3 double-knockout (DKO) iNKT cells displayed pronounced skewing toward the NKT17 lineage, with increased DNA methylation and impaired expression of genes encoding the key lineage-specifying factors T-bet and ThPOK. Transfer of purified Tet2-Tet3 DKO iNKT cells into immunocompetent recipient mice resulted in an uncontrolled expansion that was dependent on the nonclassical major histocompatibility complex (MHC) protein CD1d, which presents lipid antigens to iNKT cells. Our data indicate that TET proteins regulate iNKT cell fate by ensuring their proper development and maturation and by suppressing aberrant proliferation mediated by the T cell antigen receptor (TCR)

    Childhood acute leukemias are frequent in Mexico City: descriptive epidemiology

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    <p>Abstract</p> <p>Background</p> <p>Worldwide, acute leukemia is the most common type of childhood cancer. It is particularly common in the Hispanic populations residing in the United States, Costa Rica, and Mexico City. The objective of this study was to determine the incidence of acute leukemia in children who were diagnosed and treated in public hospitals in Mexico City.</p> <p>Methods</p> <p>Included in this study were those children, under 15 years of age and residents of Mexico City, who were diagnosed in 2006 and 2007 with leukemia, as determined by using the International Classification of Childhood Cancer. The average annual incidence rates (AAIR), and the standardized average annual incidence rates (SAAIR) per million children were calculated. We calculated crude, age- and sex-specific incidence rates and adjusted for age by the direct method with the world population as standard. We determined if there were a correlation between the incidence of acute leukemias in the various boroughs of Mexico City and either the number of agricultural hectares, the average number of persons per household, or the municipal human development index for Mexico (used as a reference of socio-economic level).</p> <p>Results</p> <p>Although a total of 610 new cases of leukemia were registered during 2006-2007, only 228 fit the criteria for inclusion in this study. The overall SAAIR was 57.6 per million children (95% CI, 46.9-68.3); acute lymphoblastic leukemia (ALL) was the most frequent type of leukemia, constituting 85.1% of the cases (SAAIR: 49.5 per million), followed by acute myeloblastic leukemia at 12.3% (SAAIR: 6.9 per million), and chronic myeloid leukemia at 1.7% (SAAIR: 0.9 per million). The 1-4 years age group had the highest SAAIR for ALL (77.7 per million). For cases of ALL, 73.2% had precursor B-cell immunophenotype (SAAIR: 35.8 per million) and 12.4% had T-cell immunophenotype (SAAIR 6.3 per million). The peak ages for ALL were 2-6 years and 8-10 years. More than half the children (58.8%) were classified as high risk. There was a positive correlation between the average number of persons per household and the incidence of the pre-B immunophenotype (Pearson's r, 0.789; P = 0.02).</p> <p>Conclusions</p> <p>The frequency of ALL in Mexico City is among the highest in the world, similar to those found for Hispanics in the United States and in Costa Rica.</p

    Correlation between work impairment, scores of rhinitis severity and asthma using the MASK-air (R) App

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    Background In allergic rhinitis, a relevant outcome providing information on the effectiveness of interventions is needed. In MASK-air (Mobile Airways Sentinel Network), a visual analogue scale (VAS) for work is used as a relevant outcome. This study aimed to assess the performance of the work VAS work by comparing VAS work with other VAS measurements and symptom-medication scores obtained concurrently. Methods All consecutive MASK-air users in 23 countries from 1 June 2016 to 31 October 2018 were included (14 189 users; 205 904 days). Geolocalized users self-assessed daily symptom control using the touchscreen functionality on their smart phone to click on VAS scores (ranging from 0 to 100) for overall symptoms (global), nose, eyes, asthma and work. Two symptom-medication scores were used: the modified EAACI CSMS score and the MASK control score for rhinitis. To assess data quality, the intra-individual response variability (IRV) index was calculated. Results A strong correlation was observed between VAS work and other VAS. The highest levels for correlation with VAS work and variance explained in VAS work were found with VAS global, followed by VAS nose, eye and asthma. In comparison with VAS global, the mCSMS and MASK control score showed a lower correlation with VAS work. Results are unlikely to be explained by a low quality of data arising from repeated VAS measures. Conclusions VAS work correlates with other outcomes (VAS global, nose, eye and asthma) but less well with a symptom-medication score. VAS work should be considered as a potentially useful AR outcome in intervention studies.Peer reviewe
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